SoCalManche

Relay in. KEY ON. Just went out and watched the voltage while cranking: drops from 4V to ~3-something V. THERE IS A NEW DEVELOPMENT. So I'm currently running my fuel pump in a 5-gal bucket of fuel to hear things better (as well as took the opportunity to clean out the tank. I can hear it prime a bit when I flip key ON. I can actually keep getting it to FIRE briefly by continually cranking, without re-adding fuel to TBI. I hear fuel returning to the bucket and dripping out briefly when key ON aka somewhat prime. This is wild. First time I've witnessed this in over a year.

Alright, unfortunate no-go. Still reading 7.9V at fuel pump connector without pump connected, and 4V with pump connected.

You're a saint.

Can't get the nut back on because the tip of the bolt is jacked up from me trying to use vice grips to rotate it out. I need to re-tap the bolt. Does it happen to say what size the bolt is in that book you have? For the dipstick tube stud.

Wow, so I am extremely confused. I went to go play with the grounds at the dipstick tube, and two wires just popped off. The eyelet they were attached to has vanished. I verified these were connected a couple days ago, yet now they are detached completely, with no eyelet in sight. I will re-crimp after I eat and cross my fingers.

Well the one black wire that splices into four black wires shoots back into the harness towards fuel pump relay. The only solid black wire coming out of the harness over there is to a three pin connector that plugs into the ICM. Don't know if that helps.

So a few things happened: Forgot the fuel pump was disconnected. Tried to crank with fuel down TBI and relay in, and it would not FIRE. While disconnected, I was checking voltages, ground at Batt Neg and power at 87, and was getting 10V; 30 was Batt voltage. The first splice was also 10V. After reconnecting pump, it fired back up no problem until fuel burned off. With KEY ON, 87 reads like 1V. Resistance is 0.L at 87, and flutters back and forth between 0.L and 0 ohms on that second splice (black splice). Second splice also had 4V with KEY ON.

Do I need to test those splices at all for anything?

I'll let the video speak for itself, ha. (I kept saying orange wire with black wiring, but meant to say orange wires with black lines) https://drive.google.com/open?id=14kY3Gwq3aaN7gohK1xHTWFttb-Cf-4U7

Looks like The Unicorn may have struck again. So as I sifted through the engine bay, I found the first spice, at it looks to be intact; https://drive.google.com/open?id=14d7HdLo9m2vOjlxLRrpk8n0eWsVqhgA5 I only have two four-pin connectors, one of which was in that mess I showed you yesterday when I started pulling split loom (https://drive.google.com/open?id=14g04avjIx-mICUV7cZyuw-4Re3OnDnqG) and then the other four-pin (https://drive.google.com/open?id=14iHlCH-FUWGw6smlrAH4yPlXhjJopyTr) I have in the engine bay is right by the battery, and looks to plug directly into that third relay (I think you said it is power steering?); also looks like the green and white wire has a little chip out of the wire insulation. Then, if you follow the harness around the block, it comes to another splice right before heading into the firewall; https://drive.google.com/open?id=14fJ-ZdS5fBxF77who01daJSDdm8mCpdS That's what I'm dealing with.

Alright, same readout regardless of jumper or relay. 7.9V disconnected FP; 4V connected FP. Is the first connection closest to relay the six-pin connection?

Yes. Do you want me to do same test with jumper?

Well then there's an issue if I'm testing properly; With KEY ON: If pump is disconnected, I get 7.9V with ground probe in A and power probe in B. When I connect pump, it drops to 4V.

Can you tell me what the voltage is supposed to be at the fuel pump harness?

T7 & 85 = Continuity, 0.2 ohms. T19 & 86 = Continuity, 0.2 ohms. D2_4 & 87 = Continuity, ~0.7 ohms. Question: when checking continuity, is it supposed to be a single beep or is it supposed to be a continuous beep, like "continuity" would assume? All three of those were a constant tone, but I checked 30 & 86 with D2_4 for giggles and they also had a constant tone with 0.3 - 0.7 ohms.

D2_7 provided the same readings across the board with KEY OFF / KEY ON / FIRE. Luckily for you, I took a slow-motion video of what is happening. This was taken with D1_3 as ground, but the same applies with D2_7 as ground. It looks like it shoots up to 5+V at the end briefly, but I don't know if that's what you're looking for. https://drive.google.com/open?id=14_K3jMBRF4caoAKcr804yVlBwfIvdf1f

I don't think so, but I will go check again.

KEY OFF: D1_3 and D2_11/D2_14, both start at 0V. KEY ON: Baseline for D2_11 and D2_14 are ~130mV. While FIRING: Sporadic voltage, staying in the mV reading. They both react the same way.

Is the ISA motor toast, or is it the ECU playing the role of electrical gremlin, causing it to not act right? Or maybe I'm wrong since it seems to be getting the proper voltage on the harness?

Glad we're all learning here! I wouldn't mind this lesson ending sooner than later, for all of our mental sakes. Here is a video of the MJ firing via fuel down TBI again, with freshly cleaned ISA. I don't necessarily know what you're looking for @eaglescout526 but it doesn't look like anything is moving; https://drive.google.com/open?id=14ZzcfRGiSK9ddeWep9ZBAZk8EQwiajYv

When I wake up, I'll do that test and send you a video. Tell SatiricalHen to PM me and I'll chat with him.

For sure. I've got a headache from the uncertainty of all this. Ha, guess I'll sift through more split loom tomorrow since I'm not sure what else to do.

All If found was that Pin 30 on FPR is supplied power by B+ Latch Relay. Not sure how, though.

Dammit, lol.

What about the B+ Latch Relay? Can we test that? I've seen other posts about that causing No-Start issues.